Dennis Lockhart, President of the Federal Reserve Bank of Atlanta, said in a speech today that improved employment in the US was enough to justify a rise in the near future.

Our baseline forecast at the Atlanta fed is for moderate growth with continuing employment gains and a gradually rising rate of inflation.

Consistent with this picture, I expect the normalization of monetary policy—that is, interest rates—to begin sometime this year. I expect normalization to proceed gradually, the implication being an environment of rather low rates for quite some time.

He did not specify whether he thought the hike should happen in September or later in the year, however.

US rates have been at their near-zero level since 2006, but the central bank has been hinting at an imminent rise for a number of months.

The consensus among analysts has been that the rise will go ahead next month, but this was thrown into question by today's huge declines across global markets.

According to CME Group FedWatch, investors now believe there is a 24 per cent chance of a rate hike happening next month – down from 51 per cent on 6 August. Earlier today, Barclays joined the debate by saying it predicted the hike would now be delayed until March next year.

In the US, the Dow, S&P 500 and Nasdaq all went down by more than three per cent today after the Shanghai Composite suffered its biggest fall since 2007.